Electronic assemblies are becoming ever more reliable in themselves, and therefore they require completely uninterruptible power supplies if this reliability is to be exploited.
There are parallel requirements for increasingly modular power supplies that are as versatile as possible as well as being highly efficient.
A first stage consists in improving the performance of primary sources of power. For example, the Applicants' French patent application No. 80 05141 for "A power distribution system for electronic assemblies" describes a power distribution system in which the primary power supplies are standardised and do not need to be regulated.
Also, particularly in telecommunications exchanges, equipment has been decentralised by supplying the racks directly with AC mains, thereby reducing the cost of transporting the electricity to its point of use while increasing modularity.
However, such decentralisation leads to an increase in the amount of equipment required at the secondary level, i.e. at rack level, thereby losing space and also losing a part of the advantages of modularity wherever the network is backed-up by a centralized emergency power supply. There is thus a requirement for a back-up supply system that is likewise modular.
Preferred embodiments of the present invention reduce the above mentioned drawbacks and can also greatly increase efficiency in the installation as a whole.